FIRE EFFECTS
SPECIES: Arctostaphylos glauca | Bigberry Manzanita 



IMMEDIATE FIRE EFFECT ON PLANT : 
Fire kills bigberry manzanita [3,9,21,30].  High-intensity fire may kill
some seed, but merely cracks the seedcoat of most seeds without harming
propagules [14].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Chaparral Populations:  Bigberry manzanita propagules germinate during
the first postfire growing season [4].  Keeley and Zedler [30] reported
a live seedling density of 280 per acre (700/ha) at postfire year 2
following the Laguna Fire in San Diego County.  Fifty-five percent of
all seedlings observed at that time were dead.  Seedlings grow rapidly
when environmental conditions are favorable.  Plants on the San Dimas
Experimental Forest in the San Gabriel Mountains attained heights of 3
to 6 feet (1-2 m) by postfire year 3 [49].  Bigberry manzanita on the
Barranca Canyon Burn near San Bernadino, California grew more slowly,
probably because precipitation was below normal during most of the first
postfire decade.  These plants were 1 inch (2.5 cm) in height at
postfire year 1 and 15.5 inches (39.4 cm) in height at postfire year 10.
Average height at postfire year 25 was 3 feet (1 m).  Many seedlings
died during a 5-year drought that began at postfire year 20 [21].

Keeley [26] reported that for plants beyond seedling size, mortality is
generally low for the first few postfire decades.  Hanes [13] stated
that by postfire year 20, bigberry manzanita has attained maximum
population size.  By the third and fourth postfire decades populations
decrease in numbers but increase in canopy cover by growth of remaining
shrubs.

Desert-edge Populations:  Seedling establishment in chaparral desert or
pinyon-juniper woodland is typically lacking or sparse following fire.
No seedling recruitment occurred following a wildfire in chaparral
desert of Anza-Borrego State Park.  Desert populations, which primarily
reproduce vegetatively, may depend upon plants in adjacent unburned
areas as important sources for postfire seed dispersal [45].  Bigberry
manzanita seedling recruitment in such communities is thusly dependent
upon animal seed dispersal followed by fire.  Fires are infrequent in
such communities, occurring approximately every 100 years [37,52].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Bigberry manzanita populations are destroyed by repeated short-interval
fires [5].  Bigberry manzanita has been eliminated from areas of the San
Dimas Experimental Forest subjected to burning at 15-year intervals
[43].  With the present man-made fire cycle of 20 to 30 years, bigberry
manzanita is expected to regenerate, but over long periods of time
sprouting species may gain an advantage [30].

Fire in summer or fall, with the wet season still to come, favors
bigberry manzanita seedling establishment over mid- to late-spring
burning because in the latter case, summer drought occurs soon after
burning [9].

Twenty percent of bigberry manzanita fuels in mixed chaparral of Camp
Pendelton, San Diego County were dead prior to a May 15 prescribed fire.
During the fire, temperatures of 1,250 degrees Fahrenheit (676 deg C)
were recorded 31 inches (79 cm) above the soil surface.  All dead and
desiccated fine bigberry manzanita fuels were consumed, and 75 percent
of green fuels were consumed [11].

Related categories for Species: Arctostaphylos glauca | Bigberry Manzanita